It's not using the background color of the inspected element

[rafaelcaricio]

The gradient examples should use the background color of the inspected element.

[gilmoreorless]

Ideally it would show whichever background colour is shown under the element, even if it's not directly on the element itself (e.g. if the element's parent has a background colour set).

This is not really possible to get 100% correct (due to positioning, images, transparencies, etc.), but a technique I've used on a previous project that gets most of the way is detailed at https://shoehornwithteeth.com/ramblings/2014/02/compute-a-dom-elements-effective-background-colour/